Haha, yes I have been beaten by some silly stuff. One of the funniest Pokemon I've come across was a choice scarf Porygon Z. I just swapped into Jellicent and laughed in it's face. My brother has lost on the frontier to a Rest, Sleep Talk, Fissure, Sheer Cold, when he was on around 70 something wins. You just can't cover every possibility with just six Pokemon, let alone three. They will eventually send a Pokemon in that your entire team cannot handle and then you are screwed.
Are you going to do a Nuzlocke challenge or something with Soul Silver?